Which of the Following Statements Is False

Which of the following statements is false?

A) A short sale is a transaction in which you buy a stock that you do not own and then agree to sell that stock back in the future.
B) The efficient portfolios are those portfolios offering the lowest possible level of volatility for a given level of expected return.
C) A positive investment in a security can be referred to as a long position in the security.
D) It is possible to invest a negative amount in a stock or security which is called a short position.